Spinal AnesthesiaPhase 4D-FAB-POURNCT07117565
D-FAB-POUR Trial: Dexmedetomidine vs Fentanyl as Adjuvants to Bupivacaine on Postoperative Urinary Retention
A Phase 4 study testing Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine and Intervention 2: Intrathecal Fentanyl with Bupivacaine in people with Spinal Anesthesia and Postoperative Complications, run by Tribhuvan University Teaching Hospital, Institute Of Medicine. at 1 site in Nepal.
Trial summary
This study aims to compare two medications, dexmedetomidine and fentanyl, when used alongside a commonly used spinal anesthetic called bupivacaine in patients undergoing lower limb surgery. Read more about this study
- Who is it for?
- Ages 18 to 60 yearsHealthy volunteers can take part
- Conditions the study is for
- Spinal Anesthesia, Postoperative Complications, Dexmedetomidine
- What is being tested?
- Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine and Intervention 2: Intrathecal Fentanyl with Bupivacaine
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 190 participants
- Where
- 1 siteNepal
- Study dates
- 15 Sep 2025to 25 Nov 2026
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Adults aged 18 to 60 years
- Scheduled for elective lower limb surgery under spinal anesthesia
- Classified as American Society of Anesthesiologists (ASA) physical status II or III
- Minimum height of 150 cm (to ensure uniform drug volume)
- Able to understand the study procedures and provide written informed consent (in English or Nepali)
Who cannot join
- Contraindications to spinal anesthesia (e.g., coagulopathy, infection at injection site, hemodynamic instability)
- Known allergy or hypersensitivity to bupivacaine, fentanyl, or dexmedetomidine
- Chronic pain conditions or long-term opioid use
- Neurological, Cardiac, Renal, or uncontrolled diabetic conditions
- Current treatment for prostatic pathology or use of alpha-2 blockers
- Presence of a Foley's catheter preoperatively
- Estimated surgical duration: >2.5 hours
- Inability or unwillingness to provide informed consent
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Nepal1 site
Om Sai Pathibhara Hospital
Bhadrapur, Koshi, 57200
Om Sai Pathibhara hospital admin, 023-453981, szndkl44@gmail.com
szndkl44@gmail.com
About this study
Official title: Comparison of Intrathecal Dexmedetomidine Versus Intrathecal Fentanyl as Adjuvants to Bupivacaine on Post-Operative Urinary Retention in Lower Limb Surgery
This study aims to compare two medications, dexmedetomidine and fentanyl, when used alongside a commonly used spinal anesthetic called bupivacaine in patients undergoing lower limb surgery. The main focus of the study is to see which combination causes fewer problems with urination after surgery - a condition known as postoperative urinary retention (POUR). POUR can lead to discomfort, delayed recovery, and a need for catheterization. Dexmedetomidine is a newer drug that may help reduce this problem compared to fentanyl, which is more commonly used but may increase the risk of urinary retention. This trial will help determine which medication combination provides better pain relief while reducing urinary side effects. The study is being conducted as a randomized, double-blind trial at a hospital in Nepal and will include 190 adult patients.
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Read the detailed description
Spinal anaesthesia is a common and effective method used to manage pain during lower limb surgeries. It allows patients to remain awake and comfortable while providing excellent pain control. To make spinal anaesthesia last longer and provide better pain relief, certain medications called adjuvants are added to the main anaesthetic drug, bupivacaine. Two commonly used adjuvants are fentanyl, an opioid, and dexmedetomidine, a medication that works on the body's alpha-2 receptors to provide sedation and pain relief.
However, a known side effect of spinal anaesthesia especially when combined with certain adjuvants is postoperative urinary retention (POUR). This condition occurs when a patient is unable to urinate normally after surgery. POUR can be uncomfortable, may delay recovery, and often requires insertion of a urinary catheter, which can increase the risk of infection and hospital stay.
This clinical trial, called the D-FAB POUR Trial, is designed to find out which of these two adjuvants dexmedetomidine or fentanyl is more likely to cause or prevent POUR when used with bupivacaine in patients undergoing elective lower limb surgery.
The study will involve 190 adult patients. Each participant will receive spinal anaesthesia with bupivacaine and be randomly assigned to also receive either dexmedetomidine or fentanyl. Neither the patients nor the doctors will know which medication is given in a process known as double-blinding to ensure fairness and eliminate bias.
The researchers will monitor the ability of patients to urinate at the third and sixth hours after surgery, using ultrasound to measure bladder volume. If the patient is unable to pass urine and the bladder is overly full, temporary or longer-term catheterisation may be needed. These outcomes will help determine how each drug affects bladder function.
In addition to urinary outcomes, the study will also look at side effects like nausea, vomiting, itching, changes in blood pressure or heart rate, sedation level, and how much extra pain relief the patient needs after surgery.
The goal of this research is to help doctors choose the best adjuvant to use in spinal anaesthesia, one that provides effective pain control without increasing the risk of urinary problems. The findings may lead to improved safety, comfort, and recovery for patients undergoing lower limb operations.
- Conditions
- Spinal Anesthesia, Postoperative Complications, Dexmedetomidine, Fentanyl, Anesthesia, Spinal, Bupivacaine
- Being tested
- Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine, Intervention 2: Intrathecal Fentanyl with Bupivacaine
- Keywords
- Postoperative urinary retention, Spinal anesthesia, Intrathecal adjuvants, Dexmedetomidine, Fentanyl, Perioperative complications
- Medical subject headings
- Postoperative Complications
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Intervention 1: Intrathecal Dexmedetomidine with BupivacaineDrug
Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine
Detailed Description:
This intervention consists of a single intrathecal injection of 10 micrograms of dexmedetomidine combined with 15 mg (3 mL) of 0.5% hyperbaric bupivacaine, administered during spinal anaesthesia for lower limb surgery. The total volume administered is 3.5 mL. Dexmedetomidine is an alpha-2 non-opioid adjuvant used as a spinal adjuvant for enhancing analgesia
Intervention 2: Intrathecal Fentanyl with BupivacaineDrug
This intervention consists of a single intrathecal injection of 25 micrograms of fentanyl combined with 15 mg (3 mL) of 0.5% hyperbaric bupivacaine, administered during spinal anesthesia for lower limb surgery. The total volume administered is 3.5 mL. Fentanyl is a lipophilic opioid commonly used as a spinal adjuvant for enhancing analgesia. This arm is being compared with dexmedetomidine to evaluate differences in POUR incidence, analgesic effectiveness, and side effect profiles.
| Study group | Role | What they receive |
|---|---|---|
| Arm 1: Dexmedetomidine Group (Group BD) | Experimental | Participants in this arm will receive 15 mg (3 mL) of 0.5% hyperbaric bupivacaine combined with 10 mcg (0.5 mL) of dexmedetomidine intrathecally. The total injected volume will be 3.5 mL. Receives: Drug: Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine |
| Arm 2: Fentanyl Group (Group BF) | Active comparator | Participants in this arm will receive 15 mg (3 mL) of 0.5% hyperbaric bupivacaine combined with 25 mcg (0.5 mL) of fentanyl intrathecally. The total injected volume will be 3.5 mL. Receives: Drug: Intervention 2: Intrathecal Fentanyl with Bupivacaine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Incidence of Postoperative Urinary Retention (POUR) at the 3rd Postoperative Hour
The primary outcome is the number of participants who are unable to void urine at the 3rd postoperative hour with a urinary bladder (UB) volume of ≥600 mL, confirmed by bladder ultrasound. Participants meeting this criterion will be considered to have postoperative urinary retention and will undergo in-out catheterization.
Measured: 3 hours after spinal anesthesia
Secondary outcomes (1)
Requirement of Urinary Catheterization at 6th Postoperative Hour
Number of participants unable to void urine by the 6th postoperative hour, requiring insertion of a Foley's catheter.
Measured: 6 hours after spinal anesthesia
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Aug 2025
- Study start15 Sep 2025 (estimated)
- Primary completion14 Sep 2026 (estimated)
- Study completion25 Nov 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Spinal AnesthesiaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- This is a parallel assignment interventional study in which participants are randomly assigned to one of two groups in a 1:1 ratio. One group receives intrathecal dexmedetomidine as an adjuvant to bupivacaine, and the other group receives intrathecal fentanyl with bupivacaine. Each participant receives only one of the study interventions throughout the trial, and no crossover occurs between groups. The study follows a prospective, double-blind, randomized controlled trial design, ensuring both the participants and investigators are blinded to group allocation.
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 190 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Tribhuvan University Teaching Hospital, Institute Of Medicine.
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Sujan Dhakal, MD, Tribhuvan University Teaching Hospital, Institute Of Medicine.
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07117565
- Sponsor's protocol ID
- D-FAB-POUR Trial
- Acronym
- D-FAB-POUR
- Status last verified
- Jun 2025
- First submitted
- 30 Jun 2025
- Last updated
- 12 Aug 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-identified individual participant data (IPD) related to primary and secondary outcomes (including urinary retention, adverse events, and analgesic requirement) will be made available upon reasonable request from qualified researchers. Data will be shared after publication of the main study findings. Access will require a data use agreement and approval by the principal investigator and ethical committee.
Study at a glance
From the registry record, last updated by the sponsor on 12 Aug 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Comparison of Intrathecal Dexmedetomidine Versus Intrathecal Fentanyl as Adjuvants to Bupivacaine on Post-Operative Urinary Retention in Lower Limb Surgery
- ClinicalTrials.gov ID
- NCT07117565
- Acronym / sponsor ID
- D-FAB-POUR / D-FAB-POUR Trial
- Conditions
- Spinal Anesthesia, Postoperative Complications, Dexmedetomidine, Fentanyl, Anesthesia, Spinal, Bupivacaine
- Keywords
- Postoperative urinary retention, Spinal anesthesia, Intrathecal adjuvants, Dexmedetomidine, Fentanyl, Perioperative complications
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 190 participants (estimated)
- Lead sponsor
- Tribhuvan University Teaching Hospital, Institute Of Medicine.University, hospital or other
- Study start
- 15 Sep 2025 (estimated)
- Primary completion
- 14 Sep 2026 (estimated)
- Study completion
- 25 Nov 2026 (estimated)
- First posted
- 12 Aug 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study aims to compare two medications, dexmedetomidine and fentanyl, when used alongside a commonly used spinal anesthetic called bupivacaine in patients undergoing lower limb surgery. The main focus of the study is to see which combination causes fewer problems with urination after surgery - a condition known as postoperative urinary retention (POUR). POUR can lead to discomfort, delayed recovery, and a need for catheterization. Dexmedetomidine is a newer drug that may help reduce this problem compared to fentanyl, which is more commonly used but may increase the risk of urinary retention. This trial will help determine which medication combination provides better pain relief while reducing urinary side effects. The study is being conducted as a randomized, double-blind trial at a hospital in Nepal and will include 190 adult patients.
-
Detailed description
Spinal anaesthesia is a common and effective method used to manage pain during lower limb surgeries. It allows patients to remain awake and comfortable while providing excellent pain control. To make spinal anaesthesia last longer and provide better pain relief, certain medications called adjuvants are added to the main anaesthetic drug, bupivacaine. Two commonly used adjuvants are fentanyl, an opioid, and dexmedetomidine, a medication that works on the body's alpha-2 receptors to provide sedation and pain relief.
However, a known side effect of spinal anaesthesia especially when combined with certain adjuvants is postoperative urinary retention (POUR). This condition occurs when a patient is unable to urinate normally after surgery. POUR can be uncomfortable, may delay recovery, and often requires insertion of a urinary catheter, which can increase the risk of infection and hospital stay.
This clinical trial, called the D-FAB POUR Trial, is designed to find out which of these two adjuvants dexmedetomidine or fentanyl is more likely to cause or prevent POUR when used with bupivacaine in patients undergoing elective lower limb surgery.
The study will involve 190 adult patients. Each participant will receive spinal anaesthesia with bupivacaine and be randomly assigned to also receive either dexmedetomidine or fentanyl. Neither the patients nor the doctors will know which medication is given in a process known as double-blinding to ensure fairness and eliminate bias.
The researchers will monitor the ability of patients to urinate at the third and sixth hours after surgery, using ultrasound to measure bladder volume. If the patient is unable to pass urine and the bladder is overly full, temporary or longer-term catheterisation may be needed. These outcomes will help determine how each drug affects bladder function.
In addition to urinary outcomes, the study will also look at side effects like nausea, vomiting, itching, changes in blood pressure or heart rate, sedation level, and how much extra pain relief the patient needs after surgery.
The goal of this research is to help doctors choose the best adjuvant to use in spinal anaesthesia, one that provides effective pain control without increasing the risk of urinary problems. The findings may lead to improved safety, comfort, and recovery for patients undergoing lower limb operations.
Study design
- Primary purpose
- Prevention
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
- Model description
- This is a parallel assignment interventional study in which participants are randomly assigned to one of two groups in a 1:1 ratio. One group receives intrathecal dexmedetomidine as an adjuvant to bupivacaine, and the other group receives intrathecal fentanyl with bupivacaine. Each participant receives only one of the study interventions throughout the trial, and no crossover occurs between groups. The study follows a prospective, double-blind, randomized controlled trial design, ensuring both the participants and investigators are blinded to group allocation.
| Arm | Type | Receives |
|---|---|---|
| Arm 1: Dexmedetomidine Group (Group BD) | Experimental | Drug: Intervention 1: Intrathecal Dexmedetomidine with BupivacaineParticipants in this arm will receive 15 mg (3 mL) of 0.5% hyperbaric bupivacaine combined with 10 mcg (0.5 mL) of dexmedetomidine intrathecally. The total injected volume will be 3.5 mL. |
| Arm 2: Fentanyl Group (Group BF) | Active comparator | Drug: Intervention 2: Intrathecal Fentanyl with BupivacaineParticipants in this arm will receive 15 mg (3 mL) of 0.5% hyperbaric bupivacaine combined with 25 mcg (0.5 mL) of fentanyl intrathecally. The total injected volume will be 3.5 mL. |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (5 listed)
- Adults aged 18 to 60 years
- Scheduled for elective lower limb surgery under spinal anesthesia
- Classified as American Society of Anesthesiologists (ASA) physical status II or III
- Minimum height of 150 cm (to ensure uniform drug volume)
- Able to understand the study procedures and provide written informed consent (in English or Nepali)
Key exclusion criteria (8 listed)
- Contraindications to spinal anesthesia (e.g., coagulopathy, infection at injection site, hemodynamic instability)
- Known allergy or hypersensitivity to bupivacaine, fentanyl, or dexmedetomidine
- Chronic pain conditions or long-term opioid use
- Neurological, Cardiac, Renal, or uncontrolled diabetic conditions
- Current treatment for prostatic pathology or use of alpha-2 blockers
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Intervention 1: Intrathecal Dexmedetomidine with BupivacaineIntervention 1: Intrathecal Dexmedetomidine with Bupivacaine Detailed Description: This intervention consists of a single intrathecal injection of 10 micrograms of dexmedetomidine combined with 15 mg (3 mL) of 0.5% hyperbaric bupivacaine, administered during spinal anaesthesia for lower limb surgery. The total volume administered is 3.5 mL. Dexmedetomidine is an alpha-2 non-opioid adjuvant used as a spinal adjuvant for enhancing analgesia | Drug | Arm 1: Dexmedetomidine Group (Group BD) |
| Intervention 2: Intrathecal Fentanyl with BupivacaineThis intervention consists of a single intrathecal injection of 25 micrograms of fentanyl combined with 15 mg (3 mL) of 0.5% hyperbaric bupivacaine, administered during spinal anesthesia for lower limb surgery. The total volume administered is 3.5 mL. Fentanyl is a lipophilic opioid commonly used as a spinal adjuvant for enhancing analgesia. This arm is being compared with dexmedetomidine to evaluate differences in POUR incidence, analgesic effectiveness, and side effect profiles. | Drug | Arm 2: Fentanyl Group (Group BF) |
Primary outcome
Incidence of Postoperative Urinary Retention (POUR) at the 3rd Postoperative Hour
Time frame: 3 hours after spinal anesthesia
The primary outcome is the number of participants who are unable to void urine at the 3rd postoperative hour with a urinary bladder (UB) volume of ≥600 mL, confirmed by bladder ultrasound. Participants meeting this criterion will be considered to have postoperative urinary retention and will undergo in-out catheterization.
1 secondary outcome
Requirement of Urinary Catheterization at 6th Postoperative Hour
Time frame: 6 hours after spinal anesthesia
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Aug 2025.
- Individual participant dataSharing planned: Yes. De-identified individual participant data (IPD) related to primary and secondary outcomes (including urinary retention, adverse events, and analgesic requirement) will be made available upon reasonable request from qualified researchers. Data will be shared after publication of the main study findings. Access will require a data use agreement and approval by the principal investigator and ethical committee.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Intervention 1: Intrathecal Dexmedetomidine with Bupivacaine and Intervention 2: Intrathecal Fentanyl with Bupivacaine in people with Spinal Anesthesia and Postoperative Complications, run by Tribhuvan University Teaching Hospital, Institute Of Medicine. at 1 site in Nepal.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 12 Aug 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Nepal. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Sujan Dhakal, MBBS,MD (+9779851325896, szndkl44@gmail.com), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Incidence of Postoperative Urinary Retention (POUR) at the 3rd Postoperative Hour (time frame: 3 hours after spinal anesthesia). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Aug 2025.